The present invention is directed to a wheelchair incorporating a container system for pressurized fluids that is lightweight and flexible.
There are many applications for a portable supply of fluid under pressure. For example, SCUBA divers and firefighters use portable, pressurized oxygen supplies. Commercial aircraft employ emergency oxygen delivery systems that are used during sudden and unexpected cabin depressurization. Military aircraft typically require supplemental oxygen supply systems as well. Such systems are supplied by portable pressurized canisters. In the medical field, gas delivery systems are provided to administer medicinal gas, such as oxygen, to a patient undergoing respiratory therapy. Supplemental oxygen delivery systems are used by patients that benefit from receiving and breathing oxygen from an oxygen supply source to supplement atmospheric oxygen breathed by the patient. Not uncommonly, patients in need of respiratory therapy are also confined to a wheelchair, or other wheeled personal transport device. For such requirements, a compact, portable supplemental oxygen delivery system is useful in a wide variety of contexts, including hospital, home care, and ambulatory settings.
High-pressure supplemental oxygen delivery systems typically include a cylinder or tank containing oxygen gas at a pressure of up to 3,000 psi. A pressure regulator is used in a high-pressure oxygen delivery system to xe2x80x9cstep downxe2x80x9d the pressure of oxygen gas to a lower pressure (e.g., 20 to 50 psi) suitable for use in an oxygen delivery apparatus used by a person breathing the supplemental oxygen.
In supplemental oxygen delivery systems, and in other applications employing portable supplies of pressurized gas, containers used for the storage and use of compressed fluids, and particularly gases, generally take the form of cylindrical metal bottles that may be wound with reinforcing materials to withstand high fluid pressures. Such storage containers are expensive to manufacture, inherently heavy, bulky, inflexible, and prone to violent and explosive fragmentation upon rupture. Mounting such containers to a wheelchair so as to provide the wheelchair patient with an portable supply of oxygen can add significant undesired weight and bulk to the wheelchair, thereby further taxing the means by which the wheelchair is propelled, whether by a motor, an assistant, or the wheelchair patient.
Container systems made from lightweight synthetic materials have been proposed. Scholley, in U.S. Pat. Nos. 4,932,403; 5,036,845; and 5,127,399, describes a flexible and portable container for compressed gases which comprises a series of elongated, substantially cylindrical chambers arranged in a parallel configuration and interconnected by narrow, bent conduits and attached to the back of a vest that can be worn by a person. The container includes a liner, which may be formed of a synthetic material such as nylon, polyethylene, polypropylene, polyurethane, tetrafluoroethylene, or polyester. The liner is covered with a high-strength reinforcing fiber, such as a high-strength braid or winding of a reinforcing material such as KEVLAR(copyright) aramid fiber, and a protective coating of a material such as polyurethane, covers the reinforcing fiber.
The design described in the Scholley patents suffers a number of shortcomings which makes it impractical for use as a container for fluids stored at the pressure levels typically seen in portable fluid delivery systems such as SCUBA gear, firefighter""s oxygen systems, emergency oxygen systems, and medicinal oxygen systems. The elongated, generally cylindrical shape of the separate storage chambers does not provide an effective structure for containing highly-pressurized fluids. Moreover, such large containers cannot be easily incorporated onto a wheelchair. Also, the relatively large volume of the storage sections creates an unsafe system subject to possible violent rupture due to the kinetic energy of the relatively large volume of pressurized fluid stored in each chamber.
Accordingly, there is a need for improved container systems made of lightweight polymeric material and which are robust and less susceptible to violent rupture and can be easily incorporated onto a wheelchair without adding significant weight or bulk to the wheelchair.
In accordance with aspects of the present invention, a wheeled personal transport device includes a gas storage vessel that is robust, unobtrusive, and lightweight.
In general, the present invention provides a wheeled personal transport device providing a portable supply of medicinal gas. The device comprises a seat adapted to support a user in a seated position, a support structure constructed and arranged to support the seat in a raised position with respect to the ground, and wheels mounted on the support structure for rolling contact with ground to permit the support structure and the seat with a user supported thereby to be rollingly transported along the ground. A gas storage vessel is carried on the support structure and comprises a plurality of hollow chambers, each having a substantially spherical or ellipsoidal shape and being formed from a polymeric material, a plurality of conduit sections formed from a polymeric material, each being positioned between adjacent ones of the plurality of hollow chambers to interconnect the plurality of hollow chambers, each of the conduit sections having a maximum interior transverse dimension that is smaller than a maximum interior transverse dimension of each of the hollow chambers, and a reinforcing filament wrapped around the hollow chambers and the conduit sections.
Other objects, features, and characteristics of the present invention will become apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of the specification, and wherein like reference numerals designate corresponding parts in the various figures.